Peak sample circuit for AC voltage and method thereof

摘要

A peak sample circuit for AC voltage, including: a rectifier coupled to receive an AC voltage and to rectify the AC voltage to generate a rectified signal; a delay circuit coupled to receive the rectified signal and to delay the rectified signal to generate a delayed rectified signal; a comparison circuit coupled to receive the delayed rectified signal and to generate a square signal based on the comparison of the rectified signal and the delayed rectified signal; and a sample output circuit coupled to receive the rectified signal, wherein the sample output circuit samples the rectified signal under the control of the square signal and provides a peak sample signal representative of the peak value of the AC voltage.

主权项

1. A peak sample circuit for AC voltage, the peak sample circuit comprising:
a rectifier having a first input terminal, a second input terminal and an output terminal, wherein the first input terminal and the second input terminal are coupled to receive an AC voltage, the rectifier rectifies the AC voltage and provides a rectified signal at the output terminal; a delay circuit having an input terminal and an output terminal, wherein the input terminal is coupled to the output terminal of the rectifier to receive the rectified signal, the delay circuit delays the rectified signal and provides a delayed rectified signal at the output terminal; a comparison circuit having a first input terminal, a second input terminal and an output terminal, wherein the first input terminal is coupled to the output terminal of the rectifier to receive the rectified signal, the second input terminal is coupled to the output terminal of the delay circuit to receive the delayed rectified signal, the comparison circuit compares the rectified signal with the delayed rectified signal and provides a square signal at the output terminal; and a sample output circuit has an input terminal, an output terminal and a control terminal, wherein the input terminal is coupled to the output terminal of the rectifier to receive the rectified signal, the control terminal is coupled to the output terminal of the comparison circuit to receive the square signal, the sample output circuit samples the rectified signal based on the square signal and provides a peak sample signal representative of the peak value of the AC voltage at the output terminal.